The present invention relates generally to fasteners and more particularly relates to fasteners having nut plates which are to be securely attached to a mounting plate.
Anchor nut fasteners are known wherein a nut plate is attached to a mounting plate. Typically, a threaded nut is retained by the nut plate in a floating manner in order to facilitate insertion of a bolt into the nut. Rotation of the nut relative to the nut plate is prevented by sidewalls of the nut plate which engage a portion of the nut.
In such fasteners, it is necessary to mount the nut plate onto the mounting plate securely and to prevent rotation of the nut plate relative to the mounting plate. In a known arrangement, the nut plate may be secured to the mounting plate by way of rivets which are provided on either side of a centrally located nut. Such an arrangement is undesirable, however, because of the need to drill three holes in the mounting plate including two holes for the rivets and one hole which provides access to the threaded nut for a threaded bolt. Especially where a significant number of such fasteners are to be used, the need to provide three relatively accurately spaced holes in the mounting plate results in a considerable expenditure of time and labor. Moreover, the three closely spaced holes may in some cases unduly weaken the mounting plate creating the potential for cracks and damage to the mounting plate
In another known arrangement for securing a nut plate to a mounting plate, rotation of the nut plate is intended to be prevented by knurling which is provided on a tubular portion of an attaching sleeve. The attaching sleeve has a flange at one end and the tubular portion is inserted through the nut plate and into a hole which has been provided in the mounting plate. The tubular portion is then deformed to retain the nut plate on the mounting plate and the knurling is intended t frictionally engage the sidewalls of the hole in the mounting plate. However, to provide the knurling on the tubular portion requires an expenditure of time and effort. Moreover, if the engagement between the knurled tubular portion and the sidewalls of the hole is not adequate or if excessive torque is applied to the nut, an unacceptable rotation of the nut plate may result.
In those arrangements where the nut plate is secured by rivets, replacement of a defective nut plate is relatively time consuming and difficult due to the need to remove the rivets.
Accordingly, it is an object of the present invention to provide a nut plate for either fixed or floating nuts which may be secured to a mounting plate without the use of rivets.
Yet another object of the present invention is to provide a nut plate in which relative rotation between the nut plate and a mounting plate on which the nut plate is fastened is prevented in an economical and efficient manner.
Still another object of the present invention is to provide a nut plate wherein the potential to unduly weaken the member on which the nut plate is fastened is reduced.
Yet still another object of the present invention is to provide an improved fastener including a nut plate and nut according to the present invention.
A still further object of the present invention is to provide an improved fastener including a nut plate and nut wherein assembly and disassembly is facilitated and the reliability of the fastener and the mounting plate is increased.
These and other objects are accomplished by a nut plate and fastener according to the present invention wherein the nut plate includes a generally flat portion which is provided with means to securely receive a nut. Means are also provided to secure the nut plate to a mounting plate with the means including a tubular portion which extends into a hole which has been provided in the mounting plate. The nut plate also includes a torque pin or projection which is spaced away from the tubular portion and which is adapted to be received within a torque pin hole or recess in the mounting plate. The projection prevents a relative rotation of the nut plate and the mounting plate.
The fastener according to the present invention comprises a nut plate including a generally flat portion which is provided with means to securely receive a nut. The nut includes a flange or skirt which is provided circumferentially about a longitudinal axis of the nut. A tubular portion of the nut extends beyond the flange and is adapted to be received within a tubular portion of the nut plate. The tubular portion of the nut plate is adapted to be deformed, swaged, spun or crimped so as to securely fasten the nut plate to a mounting plate. The nut plate also includes a torque pin or projection which is spaced away from the tubular portion and which is adapted to be received within a torque pin hole or recess in the mounting plate. The projection prevents a relative rotation of the nut plate and the member.